"I stretch my memory to when I was studying for my degree, when Timberland launched the [eco-conscious] Earthkeepers boot," Raeburn says on the phone. "I thought it was incredible to have a brand on that scale thinking so progressively all the way back in 2007. Now it's come full circle."

It was just a few months after the collaboration that Timberland announced Raeburn as the brand's first-ever global creative director, and one can imagine that things only felt more surreal from there. Though Raeburn's eponymous label has collected awards from GQ, the British Fashion Council, the Ethical Fashion Forum and more in the years since its founding in 2008, it's remained a relatively niche, albeit well-respected, company. For a giant like Timberland — which did $1.9 billion in revenue in the last fiscal year and boasts 7,000 employees worldwide — to place Raeburn at the creative helm meant the designer's reach would expand dramatically.

It's an accomplishment that would be significant to any designer on a personal level, but in Raeburn's case, there are even wider implications. Raeburn's reputation has been built equally on his innovative environmental consciousness and the strength of his design — which makes him arguably the first sustainability-centric independent designer to be granted such a prominent position at a mainstream global fashion brand.

Timberland's president Jim Pisani confirms that Raeburn's emphasis on conscious production was a part of why he was selected for the role. "[Raeburn's] passion for craftsmanship, innovation and responsible product design was a natural fit for Timberland," Pisani tells Fashionista in a phone interview. "Responsible design is a key and he's been doing this for a long time."

For those who associate Timberland and its iconic boots more with hip-hop legends than tree huggers, this internal emphasis on environmental awareness may come as a surprise. But Raeburn explains that those two have never been mutually exclusive, noting that the brand's Earthkeepers collection championed the use of recycled plastic bottles in fashion more than a decade before things like recycled plastic puffer jackets started trending.

Pisani adds that Timberland has long been a leader when it comes to higher environmental standards for tanneries, with 93 percent of the brand's leather coming from gold- or silver-rated tanneries currently — and a plan to reach 100 percent by 2020. Other ambitious goals include Timberland's intent to make all of its footwear from recycled, renewable or organic materials by 2020 ("we're currently at 67 percent," he says) and to get its apparel from 81 percent sustainably sourced — where it is today — to 100 percent over the next two years.

Despite all that Timberland's done over the last decade to inject environmental responsibility into its products, Pisani says that Raeburn's already challenged the brand to lean deeper into that instinct in his six short weeks at the brand.

"I said to [Pisani], 'You know, at points you're going to have to be comfortable with being uncomfortable,'" Raeburn explains. "I will challenge, I will push... We don't sit here for a minute thinking we have all the answers, but there's a desire to change and make a difference."

Using the learnings from his own label, where he works largely with deadstock materials like old parachutes from military surplus stores, Raeburn's been looking for ways to scale up his sustainability efforts for a company as large as Timberland. And since Timberland is just one of a portfolio of labels alongside The North Face, Vans, Wrangler and Dickies that are all owned by VF Corporation, Raeburn has hopes that any leadership Timberland takes on the sustainability front might have larger ripple effects as knowledge and resources are shared with its sister brands.

Whatever happens in the long run, Raeburn's appointment adds to the mounting evidence that ethical fashion is increasingly moving from the sidelines to the mainstream. And whether it means that massive brands start appointing more sustainable designers to major positions or not, both Raeburn and Pisani are sure of one thing: responsible manufacturing isn't a passing trend. It's the future.

"Even though it's not going to be easy and it's going to take time, it really feels like the industry is changing," Raeburn says. "Brands that are not thinking about these things are going to die. It's as simple as that."